1. Field of the Invention
This invention relates to a recording method and apparatus, to which text data or image data is inputted, for forming an image on a recording medium by bit-map development.
2. Description of the Related Art
A printer apparatus according to the prior art is constructed as shown in FIG. 6. In this arrangement, printing information (character codes and the like) sent from a host computer 31 is stored in a page buffer memory 33 via an interface 32. A character code which enters from the host computer 31 undergoes pattern development on a following RAM 39 based upon a character font that has been stored in a character-font memory 34. A pixel memory 35 stores compressed image data comprising the character data thus subjected to pattern development, or image data and the like. A parallel-serial converter 36 converts parallel data (image data), expanded and read out of the pixel memory 35, into serial data and sends the serial data to a recording unit 37. A CPU 40 has a ROM 38 and a RAM 39 and controls page editing, recording processing, and the like, based upon a control program that has been stored in the ROM 38. The RAM 39 is used as a working area during execution of various programs. The recording unit 37, which comprises a laser-beam printer or the like, causes a light beam to irradiate and scan a photosensitive drum based upon inputted image information, thereby performing recording by forming an electrostatic latent image. Numeral 41 denotes a system bus, above-described units are connected to the CPU 40 via the system bus 41.
In a case where image data is stored in the pixel memory 35 upon being compressed, the example of the prior art described above is so adapted that image data for text and image data for images is compressed at an identical ratio. As a consequence, when use is made of a compression method which employs irreversible coding, the recording quality of the text data, namely of characters, symbols, and the like, is greatly diminished.
Further, in a case where a bit-map image obtained by bit-map development of character or line-drawing data is compressed in the example of the prior art described above, the following problems arise depending upon the compression method:
(1) When a fine or slender character is recorded, the recording quality of the character undergoes a pronounced decline. This is caused by character blurring or extinction of lines, and the like.
(2) When a fine or slender line drawing is recorded, lines which should be recorded are not.